146 On the Composition and Properties of Drinking- Water, 
hard. It also contained much carbonate of lime, and about 18 
grains of sulphate of magnesia : and, in consequence of the large 
amount of earthy compounds it was excessively hard, and not 
suitable for cooking or washing purposes. Although it contained 
nothing positively injurious to health, it was too largely impi'eg- 
nated with saline matter to be ordinarily used as a beverage, 
especially as its taste and smell were objectionable. 
Properties to be preferred in a Water intended to be 
USED for Drinking and General Household Purposes. 
The properties which are esteemed of most value in water for 
drinking and general domestic purposes are :— 
1. Freedom from putrescible organic matter. 
2. Freedom from constant, or even occasional discoloration 
by clay and vegetable matter, Avith perfect brightness and 
clearness. 
3. Freedom from smell and disagreeable taste, 
4. Softness. 
5. Coolness. 
Water suitable for all domestic purposes should not contain an 
excess of saline and earthy matters, and, generally speaking, not 
more than about 25 grains of solid substances in the imperial 
gallon. The less lime and magnesia salts it contains the better 
it is for washing, or cooking, or the generation of steam in 
boilers. A moderate amount of mineral matter, or even a suf- 
ficient amount of earthy carbonates to render water decidedly 
hard, does not interfere with its use as a beverage, for it may be 
safely stated that no sufficient grounds exist for believing that 
the mineral contents of ordinary hard spring-water are injurious 
to health. The amount of lime and magnesian salts in chalk- 
springs, and in waters having their origin in calcareous strata, 
must be greatly exceeded in general by the quantity of the same 
salts which enters the system in solid food ; and it is a notorious 
fact that chalk-springs, which seldom contain less than 15 or IG 
grains of carbonate of lime, are universally considered to furnish 
perfectly wholesome, and indeed the choicest drinking-water. It 
is true that chalk-springs are wanting in softness, one of the pro- 
perties most valued in water ; but on the other hand, the uniforn 
coolness of the water at all periods of the year, its perfect bright 
ness and clearness, freedom from smell or disagreeable taste, an( 
especially its perfect freedom from organic matter capable o 
further alteration or decomposition, recommend it as an excel 
lent drinking-water. 
In point of softness, the springs in granitic regions, or district 
